That thing started an interesting conversation between the people I was watching with. My brother's friend has a Michigan grad girlfriend (she's half black) and she and I were trying to tell them that the "do" in "do-rag" is from "hairdo" as in a rag used to protect your 'do. The Sparties in the room thought it was "dew" as in a rag for collecting dew, i.e. a camping term.